Animals saw in colour long before flowers appeared

The most recent studies, published in "Biological Reviews", reveal that animals developed the ability to see colours approximately 500 million years ago, which preceded the use of colours by organisms for various functions, including reproduction.

Colours are crucial in animal communication, acting as warning or sexual signals. For instance, a peacock displays its colourful tail to attract a mate, essential in sexual selection. Vibrant colouring can also deter predators by signalling the species' toxicity.

A team of scientists, John J. Wiens from the University of Arizona, analysed the evolution of colour vision in animals. Their research demonstrated that the ability to recognise vivid colours, such as red, yellow, and blue, appeared long before the advent of colourful flowers and fruits.

Animals learned to recognise colours around 500 million years ago, whereas colourful flowers and fruits started to appear roughly 100 million years later.

The scientists discovered that warning signals in the form of bright colours evolved before sexual signals and are now five times more prevalent. Both types of signals developed approximately 100 million years ago.

Interestingly, species using these signals do not always possess advanced vision or the capability to see colours. In the case of sexual signals, both males and females must be able to distinguish colours.

Wiens emphasises that in plants, colourful signals serve two primary functions: vibrant flowers attract pollinators, and colourful fruits entice animals to disperse seeds. The studies highlight the significant role of colour vision in the evolution of animals and plants.